Although ribbon loudspeakers are capable of being designed having truly outstanding fidelity, a number of serious problems are associated with such ribbon loudspeakers. In my U.S. Pat. No. 3,564,163, incorporated by reference herein, I teach a solution to the problem of the destructive effect of standing waves upon the ribbon. In order to reduce the costs of the magnets, while maintaining reasonable efficiency, ribbon dimensions are kept small, thereby reducing the volume of the gap in the magnetic circuit and indirectly the volume of the magnets. Unfortunately, ribbon amplitude and sound power available decreases rapidly with a reduction in ribbon dimensions, and hence it is important to maximize the sound power available from a relatively small ribbon. Thus, ribbon amplitude fluctations should be considerable, which in addition to the now solved standing wave problem, permits ribbon damage by an occasional amplitude peak exceeding the elastic limit of the ribbon.
It is thus highly desirable to provide a simple and economical means of limiting ribbon amplitudes to a safe value at all times while at the same time preserving desired ribbon responsiveness.